直链化合物中α-手性碳对羰基亲核加成立体选择性的影响

Stereoselectivity in the Nucleophile Addition of Acyclicα-Chiral Carbonyl Compounds

羰基亲核加成的立体选择性常用Cram模型和Felkin-Ahn模型来判断,对于这2种反应模型的原理及它们的适用情况鲜见文章详细介绍。本文从羰基化合物的结构特点出发,分3种不同情况介绍α-手性碳对反应立体选择性的影响——没有杂原子;有杂原子无螯合效应;有杂原子且有螯合配位或氢键。将每个判断产物构型的过程清晰地分成5步,更有利于相关专业的学生进行理解记忆。

Cram model and Felkin-Ahn model have been applied to predict the stereoselectivity in the addition of nucleophiles toα-chiral carbonyl compounds.However,rare publications explain how to understand the two models thoroughly.Herein,based on conformation of carbonyls,three different situations are introduced:non heteroatom at the chiral center,a heteroatom at the chiral center without chelation and metal ion or proton capable of chelation with the heteroatom and carbonyl oxygen.Stepwise approach is introduced to predict the final configurations of products here,which is understandable and memorable.